Jealousy will soon be the subject of a global first with the development of a comprehensive new handbook, co-edited by York University psychology Professor Maria Legerstee, which will be devoted to this most fundamental of human emotions.
"The Handbook of Jealousy: Theories, Principles and Multidisciplinary Approaches" (Wiley-Blackwell Publishing) is being put together by Legerstee and her colleague Professor Sybil Hart, from the Department of Human Development & Family Studies at Texas Tech University.
Right: Maria Legerstee
The book takes on the ambitious task of unlocking the processes responsible for the unfolding of jealousy and was triggered by recent studies with infants, says Legerstee, a professor in York's Faculty of Health. It is unique because it departs from traditional approaches to examining jealousy, which emphasized the negative of this basic human emotion.
"It will be the first book of its kind," says Legerstee. "There are handbooks on many scholarly disciplines, but there is no handbook on jealousy, until now, that covers the topics that this book does."
The book will sketch a picture of jealousy, in its normative form, including its functions, origins and differentiation during infancy and childhood. The edited volume will be an interdisciplinary compilation of 20 papers and three commentaries. It will chart how jealousy unfolds and explore familial, cultural, cognitive and biological factors that drive jealousy's developmental trajectory. The list of contributors reads like a Who's Who of developmental scientists (covering both psychology and neuroscience) of the past decade.
Legerstee, who heads the Centre for Infancy Studies at York University, is a renowned psychologist whose research examines how cognitive and social factors interact in the developmental process. She says she realized there was a need for such a book when she collaborated with Hart on a colloquium on jealousy, at the Society of Research on Child Development conference held in April 2007, in Boston, Mass. Legerstee said that she was overwhelmed by the response to the colloquium. It was at that point she decided to approach Hart about publishing an edited 
volume ,not realizing that it was to become the first handbook of jealousy in the world.
Right: Legerstee with one of the Centre for Infancy Studies' youngest members
Why is there not a handbook of jealousy out there already? "Despite its ubiquity and long history of being reflected upon by theologians, philosophers, poets and psychotherapists, the topic of jealousy has only recently come to the attention of social and cognitive scientists," says Legerstee, explaining that during the 1970s, social and clinical psychologists offered frameworks that were geared largely to examining and resolving jealousy as a hindrance to love relationships, self-definition and culture.
"Around the same time," she says, "mainstream theories of emotional development suggested that jealousy could not emerge before the child was well into her second year of life because this response depends on cognitive processes (such as self-awareness, self-consciousness) that are not available before that time." As a result, treatments within the field of developmental psychology dealt with presentations subsequent to infancy and were generally limited to focusing on sibling relationships as an arena in which jealousy detracted from healthy child and family functioning.
"Though stimulating, these earlier lines of research have been challenged," says Legerstee, "adult studies have been limited by reliance on self-report measures, those using siblings have been impeded by reliance on naturalistic methods, and all have been hampered by ethical concerns leading to issues with regard to validity.
"Moreover, within frameworks in which jealousy has been conceptualized as problematic, studies often have been designed with the aim of determining under which conditions its expression and negative impact can be mitigated. Such concerns have tended to overshadow considerations of the more basic issue - how jealousy develops," she says.
Legerstee argues that "where jealousy of significant others is concerned, recent evidence from various research programs has revealed some interesting findings. Not only can jealousy of loved ones be displayed as early as the first year of life, but research has moved beyond documenting early appearance and has begun to explore other important aspects of its development, such as differences associated with maternal depression, attachment, and those manifested by children with autism who experience problems in the development of a Theory of Mind. Studies are only now beginning to develop a full understanding of jealousy during infancy and childhood.
"The Handbook of Jealousy" will be published by Wiley-Blackwell and is due to be presented to the publishers mid 2008 and to the public in 2009.
For a full synopsis of the handbook, click here.
By Jenny Pitt-Clark, YFile editor